Pressure/vacuum (pv) valve for fuel storage tanks, in-line pressure-vacuum valve test unit, and combination thereof

ABSTRACT

A flow-through pressure-vacuum valve includes a valve body having a tank-side opening and a vent-side opening. A pressure relief valve (e.g., a ball held in a corresponding seat by gravity) is positioned within a first passageway through the body. The ball is moved from the first valve seat to open the first passageway when pressure at the tank-side opening exceeds pressure at the vent-side opening by a predetermined pressure differential. A vacuum relief valve is positioned within another passageway (e.g., a serpentine passageway). The vacuum relief valve (e.g., also a ball held in a corresponding seat by gravity) is positioned within the serpentine passageway. Analogously, the ball is moved from the valve seat to open the serpentine passageway when pressure at the tank-side opening is less than the pressure at the vent-side opening by a predetermined pressure differential.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a divisional application of U.S. patent applicationSer. No. 17/566,355, filed on Dec. 30, 2021, having the title“PRESSURE/VACUUM (PV) VALVE FOR FUEL STORAGE TANKS, IN-LINEPRESSURE-VACUUM VALVE TEST UNIT, AND COMBINATION THEREOF,” which claimsthe benefit of U.S. Provisional Patent Application Ser. No. 63/131,891,filed Dec. 30, 2020, having the title “PRESSURE/VACUUM (PV) VALVE FORFUEL STORAGE TANKS, IN-LINE PRESSURE-VACUUM VALVE TEST UNIT, ANDCOMBINATION THEREOF”, the disclosures of which are hereby incorporatedby reference as if set forth expressly in their entireties.

BACKGROUND

The present disclosure relates generally to a fuel dispensing system forvehicles. More particularly, aspects of the present disclosure relate toa pressure-vacuum (PV) valve for fuel storage tanks, a venting systemincorporating the PV valve, an in-line PV valve test unit, the in-linePV valve test unit integrated into the venting system for testing the PVvalve, and combinations thereof.

Liquid fuel storage tanks, such as gasoline storage tanks, are normallyrequired to have what is commonly referred to as a Pressure/Vacuum (orPV), valve on a tank vent pipe extending between the storage tank andthe atmosphere. The purpose of a PV valve is to normally seal thestorage tank from the atmosphere so that liquid fuel, e.g., gasoline,cannot evaporate from the storage tank and escape into the atmosphere.

However, a PV valve can open at a predetermined positive pressure withinthe storage tank in order to allow the excessive positive pressurewithin the storage tank system to vent to atmosphere. The PV valve canalso open at a predetermined vacuum pressure within the storage tank inorder to allow the excessive negative pressure within the storage tanksystem to relieve relative to atmosphere.

BRIEF SUMMARY

According to aspects of the present disclosure, a flow-throughpressure-vacuum valve comprises a valve body having a tank-side openingand a vent-side opening, which can be opposite the tank-side opening. Afirst passageway extends through the valve body from the tank-sideopening to the vent-side opening. Also, a second passageway extendsthrough the valve body from the tank-side opening to the vent-sideopening. Yet further, a third passageway extends through the valve bodyfrom the tank-side opening to the vent-side opening.

A first pressure relief valve is positioned within the first passageway.The first pressure relief valve comprises a first valve seat and a firstvalve member. Here, the first valve member is moved into the first valveseat and is held therein by gravity to close the first passageway. Thefirst valve member is moved from the first valve seat to open the firstpassageway when pressure at the tank-side opening of the valve bodyexceeds pressure at the vent-side opening of the valve body by a firstpredetermined pressure differential. Gravity closes the first valvemember when pressure at the tank-side opening of the valve body nolonger exceeds pressure at the vent-side opening of the valve body bythe first predetermined pressure differential.

A second pressure relief valve is positioned within the secondpassageway. The second pressure relief valve comprises a second valveseat and a second valve member. The second valve member is moved intothe second valve seat and is held therein by gravity to close the secondpassageway. The second valve member is moved from the second valve seatto open the second passageway when pressure at the tank-side opening ofthe valve body exceeds the pressure at the vent-side opening of thevalve body by a second predetermined pressure differential, which isgreater than the first predetermined pressure differential. Gravitycloses the second valve member when pressure at the tank-side opening ofthe valve body no longer exceeds pressure at the vent-side opening ofthe valve body by the second predetermined pressure differential.

A third pressure relief valve is positioned within the third passageway.The third pressure relief valve comprises a third valve seat and a thirdvalve member. The third valve member is moved into the third valve seatand is held therein by gravity to close the third passageway. The thirdvalve member is moved from the third valve seat to open the thirdpassageway when pressure at the tank-side opening of the valve body isless than the pressure at the vent-side opening of the valve body by athird predetermined pressure differential. Gravity closes the thirdvalve member when pressure at the tank-side opening of the valve body isno longer less than the pressure at the vent-side opening of the valvebody by the third predetermined pressure differential.

According to still further aspects of the present disclosure, aflow-through pressure-vacuum valve comprises a valve body having atank-side opening and a vent-side opening. For instance, the vent-sideopening can be opposite the tank-side opening. A pressure reliefpassageway extends through the valve body from the tank-side opening tothe vent-side opening. Analogously, a vacuum release passageway extendsthrough the valve body from the tank-side opening to the vent-sideopening.

A pressure relief valve is provided within the pressure reliefpassageway. The pressure relief valve comprises a valve seat and a valvemember. The valve member of the pressure relief valve is moved into thecorresponding valve seat and is held therein by gravity to close thepressure relief passageway. The valve member is moved from the valveseat to open the pressure relief passageway when pressure at thetank-side opening of the valve body exceeds pressure at the vent-sideopening of the valve body by a first predetermined pressuredifferential.

Additionally, a vacuum relief valve is provided within the vacuumrelease passageway. The vacuum relief valve also comprises a valve seatand a valve member. The valve member of the vacuum relief valve is movedinto the corresponding valve seat and held therein by gravity to closethe vacuum relief passageway. The valve member is moved from the valveseat to open the vacuum relief passageway when pressure at the tank-sideopening of the valve body is less than the pressure at the vent-sideopening of the valve body by a predetermined pressure differential.

In some embodiments, each valve seat comprises a conical indentation inthe valve body, and each valve member comprises a free-floatingspherical ball received in the associated conical indentation so as tobe held therein by gravity. Moreover, in some embodiments, a volume ofthe second free-floating spherical ball is larger than a volume of thefirst free-floating spherical ball. Also, in some embodiments, a firstcracking pressure for the pressure relief valve is determined by a sizeof the associated free-floating spherical ball, a composition of theassociated free-floating spherical ball, a sidewall angle of theassociated conical indentation, or a combination thereof. Likewise, asecond cracking pressure, which is associated with the vacuum reliefvalve, is determined by a size of the associated free-floating sphericalball, a composition of the associated free-floating spherical ball, asidewall angle of the associated conical indentation, or a combinationthereof.

According to yet further aspects of the present disclosure, aflow-through pressure-vacuum valve system comprises a flow-throughpressure-vacuum valve, a first vent pipe section that couples theflow-through pressure-vacuum valve to a storage tank, and a second ventpipe section that couples the flow-through pressure-vacuum valve toatmosphere. Here, the flow-through pressure-vacuum valve comprises afirst pressure relief passageway coupling the first vent pipe to thesecond vent pipe, and a second pressure relief passageway coupling thefirst vent pipe to the second vent pipe. A first pressure relief valvecloses the first passageway. The first pressure relief valve comprises afirst valve seat and a first valve member, where the first valve memberis moved into the first valve seat and is held therein by gravity toclose the first passageway. The first valve member is moved from thefirst valve seat to open the first passageway when pressure in the firstvent pipe section exceeds pressure at the second vent pipe section by afirst predetermined pressure differential.

Likewise, a second pressure relief valve is provided so as to close thesecond passageway. The second pressure relief valve comprises a secondvalve seat and a second valve member. The second valve member is movedinto the second valve seat and is held therein by gravity to close thesecond passageway. In some embodiments, the second valve member is movedfrom the second valve seat to open the second passageway when pressurein the first vent pipe section exceeds the pressure at the second ventpipe section by a second predetermined pressure differential, which isgreater than the first predetermined pressure differential. In otherembodiments, the second valve member is moved from the second valve seatto open the second passageway when pressure in the first vent pipesection is less than the pressure at the second vent pipe section by asecond predetermined pressure differential.

According to further aspects of the present disclosure, a flow-throughpressure-vacuum valve comprises a valve body having a tank-side openingand a vent-side opening. A first positive pressure relief valve iswithin a first passageway. The first positive pressure relief valvecomprises a first valve seat and a first ball valve member, where thefirst ball valve member is moved into the first valve seat and is heldtherein by gravity to close the first passageway. The first ball valvemember is moved from the first valve seat by a positive pressureexceeding a first predetermined threshold. A second positive pressurerelief valve is within a second passageway. The second positive pressurerelief valve comprises a second valve seat and a second ball valvemember. The second ball valve member is moved into the second valve seatand is held therein by gravity to close the second passageway. Thesecond ball valve member is moved from the second valve seat by apositive pressure exceeding a second predetermined threshold. A negativepressure relief valve is within a third passageway. The negativepressure relief valve comprises a third valve seat and a third ballvalve member. The third valve member is moved into the third valve seatand is held therein by gravity to close the third passageway. The thirdball valve member is moved from the third valve seat by a negativepressure exceeding a predetermined threshold.

According to still further aspects herein, a flow-throughpressure-vacuum valve comprises a valve body having a tank-side openingand a vent-side opening, e.g., opposite the tank-side opening. Apositive pressure relief valve is within a corresponding passageway. Thepositive pressure relief valve comprises a valve seat and a ball valvemember, where the ball valve member is moved into the valve seat and isheld therein by gravity to close the corresponding passageway. The ballvalve member is moved from the valve seat by a positive pressureexceeding a first predetermined threshold. Additionally, a negativepressure relief valve is within a corresponding passageway. The negativepressure relief valve also comprises a valve seat and a ball valvemember, where the ball valve member is moved into the valve seat and isheld therein by gravity to close the corresponding passageway. The ballvalve member of the negative pressure relief valve is moved from itscorresponding valve seat by a negative pressure exceeding apredetermined threshold.

According to yet further aspects of the present disclosure, an in-linepressure-vacuum valve test unit comprises a body having a tank-side end,a valve-side end, and an axial passageway. The axial passageway extendsentirely through the body from the tank-side end to the valve-side endand defines a tank-side port and a valve-side port. The in-linepressure-vacuum valve test unit also comprises a test port in a sidewallof the body. A radial passageway extends from the test port into theaxial passageway. Yet further, the in-line pressure-vacuum valve testunit comprises a test probe having a hollow therethrough. The test probeis inserted into the test port such that the test probe extends throughthe radial passageway and into the axial passageway, the test probeseals the axial passageway between the tank-side port and a valve-sideport, and the hollow in the test probe cooperates with the axialpassageway to create a path through the hollow in the test probe, intothe axial passageway, and through the valve-side port.

In some embodiments, the in-line pressure-vacuum valve test unit isintegrated as part of an in-line pressure-vacuum valve test system. Inthis configuration, the in-line pressure-vacuum valve test systemincludes the in-line pressure-vacuum valve test unit described above,and a vent pipe. More particularly, a vent pipe having a first vent pipesegment is coupled to the tank-side port. The first vent pipe segmentcan couple for instance, to a storage tank. A pressure-vacuum valve(e.g., a pressure-vacuum valve according to any embodiment herein, orany other PV valve configuration) is coupled to the valve-side port ofthe in-line pressure-vacuum valve test unit, e.g., either directly orvia a second vent pipe segment. In some embodiments, the in-linepressure-vacuum valve test unit can be user installed, anduser-removable from the vent pipe. This configuration enables thein-line pressure-vacuum valve test unit to be temporarily installed,e.g., at a time of testing of the corresponding PV. In otherembodiments, the in-line pressure-vacuum valve test unit can bepermanently installed.

According to yet further aspects herein, an in-line pressure-vacuumvalve test system comprises an in-line pressure-vacuum valve test unitcomprising a body having a tank-side end, a valve-side end, and an axialpassageway extending entirely through the body from the tank-side end tothe valve-side end, where the axial passageway defines a tank-side portand a valve-side port. A test port is in a sidewall of the body, and aradial passageway extends from the test port into the axial passageway.A test probe has a hollow therethrough. The test probe is inserted intothe test port such that the test probe extends through the radialpassageway and into the axial passageway, the test probe seals the axialpassageway between the tank-side port and a valve-side port, and thehollow in the test probe cooperates with the axial passageway to createa path through the hollow in the test probe, into the axial passageway,and through the valve-side port. A vent pipe having a first vent pipesegment is coupled to the tank-side port, and a pressure-vacuum valve iscoupled to the in-line pressure-vacuum valve test unit.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is an exemplary refueling system according to aspects herein;

FIG. 2 is a perspective view of an example flow-through pressure-vacuumvalve according to aspects herein;

FIG. 3A is a top schematic view of the flow-through pressure-vacuumvalve of FIG. 2 illustrating various cross sections;

FIG. 3B is a bottom schematic view of the flow-through pressure-vacuumvalve of FIG. 3A, illustrating various cross sections where theillustrated view is inverted for convenience of correspondence with FIG.3A;

FIG. 4 is a cross-sectional view of the flow-through pressure-vacuumvalve of FIG. 3 along line A-A, according to aspects herein;

FIG. 5 is a cross-sectional view of the flow-through pressure-vacuumvalve of FIG. 3 along line B-B, according to aspects herein;

FIG. 6 is a cross-sectional view of the flow-through pressure-vacuumvalve of FIG. 3 along line C-C, according to aspects herein;

FIG. 7 is a cross-sectional view of the flow-through pressure-vacuumvalve of FIG. 3 along line D-D, according to aspects herein;

FIG. 8 is a cross-sectional view of the flow-through pressure-vacuumvalve of FIG. 3 along line E-E, according to aspects herein;

FIG. 9 is an example in-line pressure-vacuum valve test unit accordingto aspects herein;

FIG. 10 is an example top view of the in-line pressure-vacuum valve testunit of FIG. 9 ;

FIG. 11 is an example bottom view of the in-line pressure-vacuum valvetest unit of FIG. 9 ;

FIG. 12 is a cross-sectional view of the in-line pressure-vacuum valvetest unit of FIG. 9 , taken along lines A-A of FIG. 11 , showing aninstalled cap;

FIG. 13 is a view of an example test probe for use with an in-linepressure-vacuum valve test unit;

FIG. 14 is an example test probe;

FIG. 15 is a break apart diagram of a vent pipe assembly having apressure-vacuum valve and an in-line pressure-vacuum valve test unit,according to aspects herein;

FIG. 16 is an assembled view of the components of FIG. 15 ; and

FIG. 17 is a cross sectional view illustrating an examplepressure-vacuum valve attached upstream of an in-line pressure-vacuumvalve test unit, according to aspects herein.

DETAILED DESCRIPTION

According to various aspects of the present disclosure, a flow-throughpressure-vacuum valve is provided for use with a venting system for fuelstorage tanks, e.g., underground fuel storage tanks. Conventionalpressure-vacuum valves are complex, often requiring springs, elaborateflow paths, and mechanical components that wear out or break over time.This complexity is particularly problematic for pressure-vacuum valvesthat are made of plastic. In this regard, it is possible that aconventional pressure-vacuum valve must be replaced frequently, e.g., asfrequent as annually. However, aspects herein provide a pressure-vacuumvalve that is simple, reliable, and includes a minimal number of movingparts. Moreover, aspects herein provide a pressure-vacuum valve that isfield serviceable to clean the valve and provides parts that aredurable, even with regard to withstanding harsh environments.

Pressure-Vacuum Valve

Referring now to the drawings, and in particular to FIG. 1 , an examplerefueling station 10 is illustrated according to aspects herein. Ingeneral, a refueling system dispenser 12 is utilized to pump fuel, e.g.,gasoline, into a vehicle 14. To accomplish this refueling task, therefueling system dispenser 12 pumps fuel from a fuel storage tank (e.g.,implemented as an underground storage tank) 16 through the refuelingsystem dispenser 12 and into a suitable holding tank on the vehicle 14.

Replenishing the fuel in the underground storage tank 16, e.g., from atanker truck (not shown), and dispensing fuel from the undergroundstorage tank 16 to the vehicle 14 displaces a mixture of fuel vapor andair inside the underground storage tank 16. Such activities can createcircumstances where there is over or under pressure in the undergroundstorage tank 16. To address over pressure and under pressure situations,a vent pipe 18 couples an interior volume of the underground storagetank 16 to atmosphere. For instance, as illustrated, the vent pipe 18comprises a first vent pipe section 20, a second vent pipe section 22,and a vent cap 24. Additionally, a pressure-vacuum valve 26 is providedin-line, somewhere along the length of the vent pipe 18.

For instance, as illustrated, the pressure-vacuum valve 26 isimplemented as a flow-through pressure-vacuum valve 26 situated in-linebetween the first vent pipe section 20 and the second vent pipe section22. In this regard, the first vent pipe section 20 couples theflow-through pressure-vacuum valve 26 to an internal volume of theunderground storage tank 16. Correspondingly, the second vent pipesection 22 couples the flow-through pressure-vacuum valve 26 toatmosphere, e.g., via the vent cap 24. In this regard, the vent cap 24prevents water and other contaminants from entering the vent pipesection 22 at the distal end relative to the flow-throughpressure-vacuum valve 26. Here, the vent pipe 18, in cooperation withthe flow-through pressure-vacuum valve 26, forms a flow-throughpressure-vacuum valve system 28.

In some embodiments, it is possible to position the pressure-vacuumvalve 26 towards the distal end of the vent pipe 18, e.g., bypositioning the pressure-vacuum valve 26 adjacent to the vent cap 24.However, in practical embodiments herein, it is also possible toposition the pressure-vacuum valve 26 along the vent pipe 18 to aposition that makes the pressure-vacuum valve 26 relatively easier toservice. Note here that performance is not affected since the venting toatmosphere occurs at the vent cap 24 regardless of where thepressure-vacuum valve 26 is located in-line along the vent pipe 18.

By way of illustration, and not by way of limitation, the vent pipe 18may be approximately 12 feet (approximately 3.66 meters) tall, e.g.,from the surface from which the vent pipe 18 emerges from theunderground storage tank 16, e.g., the ground level, extendingvertically to the vent cap 24. In an example embodiment, theflow-through pressure-vacuum valve 26 is connected into the first ventpipe section 20 so as to position the flow-through pressure-vacuum valve26 at a height of less than six feet (less than approximately 1.83meters) from the surface (e.g., ground level) from which the vent pipe18 emerges from the fuel storage tank. Other heights/positions along thevent pipe 18 can alternatively be implemented.

In example implementations, an optional in-line pressure-vacuum valvetest unit (not shown) is in-line with the vent pipe 18 (or can betemporarily installable in-line with the vent pipe 18) below theflow-through pressure-vacuum valve 26. The in-line pressure-vacuum valvetest unit enables test-in-place capability for testing the flow-throughpressure-vacuum valve 26, examples of which are described more fullyherein.

In a particular embodiment, the flow-through pressure vacuum valve 26 isconnected into the first vent pipe section 20 so as to position theflow-through pressure-vacuum valve 26 at a height of up to four feet(approximately 1.22 meters) from the surface (e.g., ground level) fromwhich the vent pipe 18 emerges from the fuel storage tank 16. In exampleimplementations, an in-line pressure-vacuum valve test unit (not shown)can be optionally in-line with the vent pipe 18 (or can be temporarilyinstallable in-line with the vent pipe 18) below the flow-throughpressure-vacuum valve 26, as noted above.

Traditionally, a pressure-vacuum valve 26 is installed at the top of thevent pipe 18, e.g., just below the vent cap 24. Here, the vent pipe 18can be about twelve feet (12′ or approximately 3.66 meters) above groundlevel in accordance with requirements set by national and local firecodes. With the pressure-vacuum valve 26 installed at such a height,installation, removal, maintenance and testing of the pressure-vacuumvalve 26 is prohibitive, necessitating the use of a ladder or a portablelift. Currently, typical practice requires the use of a portable liftfor any work related to a pressure-vacuum valve 26 installed at a heightnear the top of the vent pipe 18 due to safety concerns, which makessuch work relatively expensive. However, aspects herein provide aflow-through pressure-vacuum valve 26, allowing the pressure-vacuumvalve 26 to be positioned in-line with the vent pipe 18, e.g., at aheight that allows inspection and servicing without requiring specialequipment to reach the top of the vent pipe 18.

Referring to FIG. 2 , a perspective view of the flow-throughpressure-vacuum valve 26 is illustrated. For instance, as illustrated,the flow-through pressure-vacuum valve 26 has a valve body 32 defined byan optional vent-side flanged member 34, a valve body section 36, and anoptional tank-side flanged member 38. The tank-side flanged member 38includes a tank-side internal receiver 40 (e.g., internally threadedportion, socket, etc.), that enables rapid assembly to a first vent pipesection (e.g., the first vent pipe section 20, FIG. 1 ). Analogously,the vent-side flanged member 34 includes a vent-side internal receiver42 (e.g., internally threaded portion, socket, etc.), that enables rapidassembly to the second vent pipe section (e.g., the second vent pipesection 22, FIG. 1 ). For sake of illustration, the vent-side flangedmember 34, the valve body section 36, and the tank-side flanged member38 are coupled in sealingly tight relationship using one or morefasteners, e.g., bolts 44. Other configurations of connecting theflow-through pressure-vacuum valve 26 to a corresponding vent pipe maybe implemented.

Thus, in the example embodiment, the flow-through pressure-vacuum valve26 is illustrated as having a valve body 32 having a tank-side opening46 and a vent-side opening 48. In practical embodiments, the tank-sideopening 46 is opposite the vent-side opening 48.

As will be described in greater detail herein, the flow-throughpressure-vacuum valve 26 includes one or more valves that open inresponse to a pressure differential between the tank-side (i.e., towardsthe tank-side flanged portion—e.g., the tank-side opening 46) and thevent-side (i.e., to wards the vent side flanged member 34—e.g., thevent-side opening 48). In other characterizations, the pressuredifferential can be considered between the first vent pipe section 20and the second vent pipe section 22. In yet other characterizations, thepressure differential can be considered between the storage tank 16 andatmosphere.

As an example, a first pressure relief valve may be implemented as afirst positive pressure relief valve within a first passageway. Forinstance, the first positive pressure relief valve can comprise a firstvalve seat and a first ball valve member within an axial segment of thefirst passageway. Here, “axial” is in the vertical orientation whenproperly installed, so that gravity can transition the first ball valvemember into its valve seat, e.g., to close the valve, and hence, closethe first passageway. In some embodiments, the axial segment can becoupled via one or more transverse segments. Here, a “transverse’segment is orthogonal to the axial segment (e.g. in a horizontalorientation). The first ball valve member is moved into the first valveseat and is held therein by gravity to close the first passageway. Thefirst ball valve member is moved from the first valve seat by a positivepressure (e.g. higher pressure at the tank-side opening relative to thepressure at the vent-side opening) exceeding a first predeterminedthreshold. Gravity closes the first valve member when pressure at thetank-side opening of the valve body no longer exceeds pressure at thevent-side opening of the valve body by the first predetermined pressuredifferential.

Analogously, a second pressure relief valve can be provided. Forinstance, the second pressure relief valve can be implemented as asecond positive pressure relief valve within a second passageway. Forinstance, the second pressure relief valve can be positioned within anaxial segment of the second passageway. Here, the second positivepressure relief valve can comprise a second valve seat and a second ballvalve member. The second ball valve member is moved into the secondvalve seat and is held therein by gravity to close the secondpassageway. The second ball valve member is moved from the second valveseat by a positive pressure (e.g. higher pressure at the tank-sideopening relative to the pressure at the vent-side opening) exceeding asecond predetermined threshold. Gravity closes the second valve memberwhen pressure at the tank-side opening of the valve body no longerexceeds pressure at the vent-side opening of the valve body by thesecond predetermined pressure differential. In example configurations,the second predetermined threshold is greater than the firstpredetermined threshold.

Similarly, a third pressure relief valve can be provided. For instance,the third pressure relieve valve can be implemented as a negativepressure relief valve (or a vacuum relief valve) within a thirdpassageway. For instance, the third pressure relief valve can bepositioned within an axial segment of the third passageway. Here, thenegative pressure relief valve can comprise a third valve seat and athird ball valve member. The third valve member is moved into the thirdvalve seat and is held therein by gravity to close the third passageway.The third ball valve member is moved from the third valve seat by anegative pressure (e.g. lower pressure at the tank-side opening relativeto the pressure at the vent-side opening) exceeding a thirdpredetermined threshold. Gravity closes the third valve member whenpressure at the tank-side opening of the valve body is no longer lessthan the pressure at the vent-side opening of the valve body by thethird predetermined pressure differential.

Referring to FIG. 3A, a top schematic view of the valve body section 36is illustrated. Referring to FIG. 3B, a bottom schematic viewillustrates the valve body section 36 of FIG. 3A. In FIG. 3B, the viewis inverted so that the view is of the bottom face but looking “topdown” so that the cross-section lines and features align for easy visualreference.

Generally, there are between one and three valves located within thevalve body section 36 of the flow-through pressure-vacuum valve.Referring now to FIGS. 3A and 3B, by way of example, a first valve(e.g., V1) can respond to positive pressure built up in a correspondingstorage tank (see underground storage tank 16, FIG. 1 ). A second valve(e.g., V2, which is optional) can respond to significant positivepressure buildup in the storage tank. For instance, the second valve canprovide emergency venting of the storage tank in the case of a rapidincrease in pressure within the storage tank, such as could occur duringa fuel drop, i.e., fuel delivery. A third valve (e.g., V3) can respondto negative pressure (vacuum) in the storage tank, and thus defines avacuum relief valve.

In the illustrated embodiment, each valve, (e.g., V1, V2, and V3) islocated in a corresponding axial segment of a corresponding passageway(oriented vertically when installed per FIG. 1 ). This allows gravity tobe used to close each valve. The valve body section 36 can include otherpassageway segments, including a first axial passageway segment AP1, anda second axial passageway segment AP2. Still further, the valve bodysection 36 can include transverse passageway segment(s), e.g., apassageway segment that is orthogonal to an axial passageway segment.

By way of example, as illustrated in FIG. 3B, a first transversepassageway segment TP1 may couple V1 to V2 about a bottom portion of thevalve body section 36. Continuing with this example, as illustrated inFIG. 3A, a second transverse passageway segment TP2 may couple V1 to V2about a top portion of the valve body section 36. Also, a thirdtransverse passageway segment TP3 may couple V2 to AP1 about the topportion of the valve body section 36. Referring to FIG. 3B, a fourthtransverse passageway segment TP4 may couple AP1 to V3 about the bottomportion of the valve body section 36. Referring back to FIG. 3A, a fifthtransverse passageway segment TP5 may couple V3 to AP2 about the topportion of the valve body section 36. Referring again to FIG. 3B, asixth transverse passageway segment TP6 may couple AP2 to V2 about thebottom portion of the valve body section 36.

In general, the combination of valves, axial passageway segments andtransverse passageway segments enables each valve to operate in agravity driven configuration even though V1 and V2 are positive pressurevalves and V3 is a negative pressure valve, as described more fullyherein. Moreover, as illustrated in FIG. 3A and FIG. 3B, each“passageway” can include any combination of one or more axial segments,transverse segments, or combinations thereof.

To illustrate the functioning of the flow-through pressure-vacuum valve26, several cross-sections are provided, including a first cross-sectionalong line A-A, a second cross-section along line B-B, a thirdcross-section along line C-C, a fourth cross-section along line D-D, anda fifth cross-section along line E-E.

Referring to FIG. 4 , a cross-sectional view of the flow-throughpressure-vacuum valve of FIG. 3 along line A-A is illustrated accordingto aspects herein. In this example, the valve body 32 has a tank-sideopening 46 and a vent-side opening 48 and illustrates exampleconfigurations for positive pressure relief valve(s).

As illustrated, a first passageway 50 extends through the valve body 32from the tank-side opening 46 to the vent-side opening 48. As will beseen, this forms the seating location of a positive pressure valve.Where an optional second positive pressure valve is provided (e.g., anemergency venting valve), a second passageway 52 extends through thevalve body 32 from the tank-side opening 46 to the vent-side opening 48.

In the illustrated embodiment, a first pressure relief valve 54 ispositioned within the first passageway 50 (e.g., see V1—FIG. 3A and FIG.3B). For instance, the first passageway 50 can comprise an axiallyextending segment (e.g., a single axial segment as shown), which canoptionally couple to transverse segment(s), an example of which isdiscussed below. Here, the first pressure relief valve 54 is positionedwithin the axially extending segment of the first passageway 50.Regardless, the first pressure relief valve 54 comprises a first valveseat 56 and a first valve member 58. The first valve member 58 is movedinto the first valve seat 56 and is held therein by gravity to close thefirst passageway 50 (e.g., from completing an open path from thetank-side to the vent-side). The first valve member 58 is moved from thefirst valve seat 56 to open the first passageway 50 when pressure at thetank-side opening of the valve body 32 exceeds pressure at the vent-sideopening of the valve body 32 by a first predetermined pressuredifferential. Due to gravity, when the pressure differential relative toeach side of the first valve member 58 falls below the firstpredetermined pressure differential, the first valve member 58 onceagain closes, thus sealing the first passageway 50.

Where a second positive pressure relief valve (e.g., emergency reliefvalve) is included, a second pressure relief valve 60 is provided withinthe second passageway 52 (e.g., see V2—FIG. 3A and FIG. 3B). Analogousto that above, in an example embodiment, the second passageway 52comprises an axially extending segment (e.g., a single axial segment asshown), in which the second pressure relief valve 60 is positioned. Thesecond pressure relief valve 60 comprises a second valve seat 62 and asecond valve member 64. The second valve member 64 is moved into thesecond valve seat 62 and is held therein by gravity to close the secondpassageway 52 (e.g., from completing an open path from the tank-side tothe vent-side). The second valve member 64 is moved from the secondvalve seat 62 to open the second passageway 52 when pressure at thetank-side opening of the valve body exceeds the pressure at thevent-side opening of the valve body 32 by a second predeterminedpressure differential, which is greater than the first predeterminedpressure differential. Due to gravity, when the pressure differentialrelative to each side of the second valve member 64 falls below thesecond predetermined pressure differential, the second valve member 64once again closes, thus sealing the second passageway 52.

In an example embodiment, assume the valve body 32 includes a firstpositive pressure relief valve (e.g., first pressure relief valve 54)and a second, emergency relief valve (e.g., second pressure relief valve60). In this configuration, the first passageway 50 can follow a routethat includes include a first transverse segment 50A (e.g., see TP1—FIG.3B), a first axial segment 50B (e.g., see V1—FIG. 3A and FIG. 3B), and asecond transverse segment 50C (e.g., see TP2—FIG. 3A). The firsttransverse segment 50A can be positioned along the bottom of the valvebody 32 so as to connect the tank-side opening 46 of the valve body 32(e.g., via the second passageway 52) to the axial segment 50B of thefirst passageway 50 (which contains the first pressure relief valve 54).Correspondingly, the second transverse segment 50C can be positionedalong the top of the valve body 32 so as to connect the vent-sideopening 48 of the valve body 32 (e.g., via the second passageway 52) tothe axial segment 50B of the first passageway 50.

In some embodiments, the first passageway 50 can include multiple axialsegments, e.g., by considering a portion (e.g., an axial segment) of thesecond passageway 52 that couples the tank-side opening 46 to the firsttransverse segment 50A and/or by considering a portion (e.g., an axialsegment) of the second passageway 52 that couples the vent-side opening48 to the second transverse segment 50C.

By comparison, in this example, the second passageway 52 can define a“through” axial passageway (second axial segment 52A) that extendsentirely through the valve body 32, from the bottom to the top, definingan axially extending aperture from a tank-side opening 46 to a vent-sideopening 48. This provides a direct, straight path for a large pressurebuild up to escape from the tank (not shown) to atmosphere.

Thus, two separate positive pressure flow paths are provided using thesame tank-side opening 46 and vent-side opening 48 of the valve body 32.Moreover, as illustrated, the first passageway 50 and the secondpassageway 52 can share a common tank-side opening 46 and/or vent-sideopening 48, such as by using one more transverse passageways to couple acommon tank-side opening 46 and/or vent-side opening 48 to each axiallyoriented positive pressure valve.

Referring to FIG. 3A, FIG. 3B, FIG. 5 , FIG. 6 , FIG. 7 , and FIG. 8generally, a vacuum-side relief valve system can also be implementedusing a gravity valve configuration.

In the illustrated embodiment, a third passageway 66 extends through thevalve body 32 from the vent-side opening 48 to the tank-side opening 46following a series of segments, e.g., in a “serpentine” pattern thatwinds through the valve body section 36 in a series of connected axialand transverse segments, as described in greater detail below.

FIG. 5 is a cross-sectional view of the flow-through pressure-vacuumvalve of FIG. 3A and FIG. 3B along line B-B. With reference to FIG. 5 ,assume a negative pressure buildup at the underground storage tank (notshow). Responsive thereto, a positive pressure will flow into the valvebody section 36 via the vent-side opening 48. In this illustrativeembodiment, the pressure enters generally over the second passageway 52.In this situation, the second pressure relief valve 60 is closed,preventing the pressure to pass directly through the valve body section36. The relatively higher pressure above the second pressure reliefvalve 60 ensures that the second pressure relief valve will not open.Analogously, although not shown in FIG. 5 , the first pressure reliefvalve 54 also remains closed, preventing the pressure from passingthrough the valve body section 36 via the first passageway 50, foranalogous reasons.

However, segments of the third passageway 66 are open. For instance, asillustrated, a third transverse segment 66A (e.g., TP3—FIG. 3A) couplesthe second passageway 52 to a third axial segment 66B (e.g., AP1—FIG.3A, FIG. 3B).

FIG. 6 is a cross-sectional view of the flow-through pressure-vacuumvalve of FIG. 3A and FIG. 3B along line C-C. Referring to FIG. 6 , thepressure can flow from the third transverse segment 66A to the thirdaxial segment 66B as described with reference to FIG. 5 . The thirdpassageway 66 further couples from the third axial segment 66B to afourth transverse segment 66C (e.g., TP4—FIG. 3B). The fourth transversesegment 66C couples the third axial segment 66B to a third pressurerelief valve 70 (e.g., V3—FIG. 3A, FIG. 3B), which is located in afourth axial segment 66D.

The third pressure relief valve 70 (vacuum relief valve) comprises athird valve seat 72 and a third valve member 74. The third valve member74 is moved into the third valve seat 72 and is held therein by gravityto close the third passageway 66 (e.g., from completing an open pathfrom the tank-side to the vent-side). The third valve member 74 is movedfrom the third valve seat 72 to open the third passageway 66 whenpressure at the tank-side opening of the valve body 32 is less than thepressure at the vent-side opening of the valve body by a thirdpredetermined pressure differential (i.e., a vacuum). Notably, becauseof the serpentine pattern of the third passageway 66, the positivepressure is now below the third valve member 74, and the negativepressure is above the third valve member 74 due to the serpentinepattern of the third passageway (as will be described in furtherdetail).

When the pressure differential exceeds a predetermined threshold, thisallows the third valve member 74 to temporarily unseat, allowing thepressure to equalize. Due to gravity, when the pressure differentialrelative to each side of the third valve member 74 falls below the thirdpredetermined pressure differential, the third valve member 74 onceagain closes due to gravity.

The flow continues up the fourth axial segment 66D to a fifth transversesegment 66E (e.g., TP5—FIG. 3A).

FIG. 7 is a cross-sectional view of the flow-through pressure-vacuumvalve of FIG. 3A and FIG. 3B along line D-D. Referring to FIG. 7 , asnoted with regard to FIG. 6 , the flow, upon the pressure differentialexceeding the threshold for the third pressure relief valve 70, flows upthe fourth axial segment 66D, and across the fifth transverse segment66E to a fifth axial segment 66F (e.g., AP2—FIG. 3A, FIG. 3B). The flowcontinues from the fifth axial segment 66F to a sixth transverse segment66G (e.g. TP6—FIG. 3B).

FIG. 8 is a cross-sectional view of the flow-through pressure-vacuumvalve of FIG. 3A and FIG. 3B along line E-E. Referring to FIG. 8 , asnoted with reference to FIG. 7 , the flow continues from the fifthtransverse segment 66E to the fifth axial segment 66F, and from thefifth axial segment 66F to the sixth transverse segment 66G. The sixthtransverse segment 66G couples the fifth axial segment 66F back to thesecond passageway 52, where the flow can continue out the tank-sideopening 46.

Referring to FIG. 5 , FIG. 6 , FIG. 7 , and FIG. 8 generally, in theillustrated example embodiment, the third pressure relief valve 70 canbe implemented as a negative pressure relief valve within the thirdpassageway 66 due to the serpentine pattern that allows positivepressure to work against gravity. In summary, FIG. 5 , FIG. 6 , FIG. 7 ,and FIG. 8 clarify the flow path to operate the third pressure reliefvalve 70, which can be seen with reference to FIGS. 3A and 3B.

Analogously, with brief reference back to FIGS. 3A and 3B, a flow tooperate the third pressure relief valve can be seen as a positivepressure entering the vent-side opening of the valve body axially,entering the valve body via an axial segment of the second passageway(entering from above V2), traversing across an upper portion of thevalve body via TP3, flowing axially down AP1 towards a bottom portion ofthe valve body, traversing across a bottom portion of the valve body viaTP4, pushing axially up against V3 to open the third pressure reliefvalve 70 to transition back to an upper portion of the valve body,traversing across TP5 to AP2, axially flowing down TP5 back towards thebottom portion of the valve body, traversing across TP6 back to asegment of the second passageway towards the bottom (below V2), andaxially exiting the tank-side opening.

As another example configuration, a characterization of the thirdpassageway can generally comprise a first axially extending (passageway)segment coupling the vent-side opening of the valve body to a firsttransverse (passageway) segment, a second axially extending (passageway)segment coupling the first transverse (passageway) segment to a secondtransverse (passageway) segment, and a third axially extending(passageway) segment coupling the second transverse (passageway) segmentto the tank-side opening of the valve body, where the third pressurerelief valve is positioned in the second axially extending (passageway)segment.

With reference to FIG. 3A through FIG. 8 generally, in an exampleembodiment, the first valve seat 56 of the first pressure relief valve54 can comprise a first conical indentation in the valve body.Correspondingly, the first valve member 58 can comprise a firstfree-floating spherical ball received in the first conical indentationso as to be held therein by gravity. Analogously, the second valve seat62 of the second pressure relief valve 60 can comprise a second conicalindentation in the valve body. Correspondingly, the second valve member64 can comprise a second free-floating spherical ball received in thesecond conical indentation so as to be held therein by gravity. Yetanalogously, the third valve seat 72 of the third pressure relief valve70 can comprise a third conical indentation in the valve body.Correspondingly, the third valve member 74 can comprise a thirdfree-floating spherical ball received in the third conical indentationso as to be held therein by gravity.

In a practical application, the first free-floating spherical ball(“normal” positive pressure relief) is the smallest, the secondfree-floating spherical ball (“large” positive pressure relief) is thelargest, and the third free-floating spherical ball (negative pressurerelief) is medium sized, having a size between the first free-floatingspherical ball and the second free-floating spherical ball. Thus, avolume of the second free-floating spherical ball is larger than avolume of the first free-floating spherical ball, and a volume of thethird free-floating spherical ball is larger than the volume of thefirst free-floating spherical ball and the volume of the thirdfree-floating spherical ball is smaller than the volume of the secondfree-floating spherical ball. In other applications, the spherical ballscan be the same size, or each spherical ball can have a size, weight, orcombination thereof, which is designated by the function that thespherical ball is intended to perform, e.g., unseat against the pull ofgravity to transition a pressure difference that exceeds a predeterminedpressure differential. Notably, because each spherical ball seats in acorresponding conical indentation, each valve can function as a one-wayvalve, only opening against gravity, e.g., when a pressure below thecorresponding spherical ball exceeds the pressure above the sphericalball by a designed for threshold (based upon ball size, ball weight,seat configuration, combination thereof, etc.,). Upon pressureequalization or at least pressure difference relief below the associatedthreshold, gravity pulls the spherical ball back into the correspondingconical indentation.

In some embodiments, a first shelf at least partially surrounds thefirst valve seat. The first shelf is inclined to return the firstfree-floating spherical ball to the first conical indentation bygravity. This incline provides a place for the valve member to traveluntil gravity pulls the valve member back into the corresponding seat.In a practical application, the incline can fan out, e.g., up to 80degrees. In other applications, the fan out can be more than 80 degrees.

Analogously, in some embodiments, a second shelf at least partiallysurrounds the second valve seat. The second shelf is analogouslyinclined to return the second free-floating spherical ball to the secondconical indentation by gravity. This incline provides a place for thevalve member to travel until gravity pulls the valve member back intothe corresponding seat. In a practical application, the incline can fanout, e.g., up to approximately 50 degrees. In other applications, thefan out can be more than 50 degrees.

Likewise, in some embodiments, a third shelf at least partiallysurrounds the third valve seat. The third shelf is inclined to returnthe third free-floating spherical ball to the third conical indentationby gravity. This incline provides a place for the valve member to traveluntil gravity pulls the valve member back into the corresponding seat.In a practical application, the incline can fan out, e.g., up to 100degrees. In other applications, the fan out can be over 100 degrees.

Yet further, in some embodiments, the flow-through pressure-vacuum valvecan comprise a first shelf at least partially surrounding the firstvalve seat, where the first shelf is inclined to return the firstfree-floating spherical ball to the first conical indentation bygravity. Likewise, the flow-through pressure-vacuum valve can comprise asecond shelf at least partially surrounds the second valve seat, wherethe second shelf is inclined to return the second free-floatingspherical ball to the second conical indentation by gravity. Yetfurther, the flow-through pressure-vacuum valve can comprise a thirdshelf at least partially surrounding the third valve seat, where thethird shelf is inclined to return the third free-floating spherical ballto the third conical indentation by gravity.

In general, the incline in the shelf for each valve member can be thesame or different. For instance, the first shelf can exhibit an anglehaving a value that is greater than that of the second shelf, but thatis smaller than that of the third shelf. In an example embodiment, theincline of the first shelf is at approximately 60 degrees, the inclineof the second shelf is at approximately 20 degrees, and the incline ofthe third shelf is at approximately 100 degrees.

In practice, a first cracking pressure for the first pressure reliefvalve (corresponding to the first predetermined pressure differential)can be determined by a ball size of the first free-floating sphericalball, a composition of the first free-floating spherical ball, asidewall property (such as angle, dimensions, surface, etc.,) of thefirst conical indentation, or a combination thereof. Similarly, a secondcracking pressure for the second pressure relief valve (corresponding tothe second predetermined pressure differential) can be determined by aball size of the second free-floating spherical ball, a composition ofthe second free-floating spherical ball, a sidewall property (such asangle, dimensions, surface, etc.,) of the second conical indentation, ora combination thereof. Yet further, a third cracking pressure for thethird pressure relief valve (corresponding to the third predeterminedpressure differential) can be determined by a size of the thirdfree-floating spherical ball, a composition of the third free-floatingspherical ball, a sidewall property (such as angle, dimensions, surface,etc.,) of the third conical indentation, or a combination thereof.

In an example embodiment, the valve body 32 is comprised of a materialsuch as aluminum. The first free-floating spherical ball is made ofstainless steel, the second free-floating spherical ball is made ofstainless steel, and the third free-floating spherical ball is made ofstainless steel. In this regard, to facilitate machining, a first insert80 (see FIG. 4 ) can be press fit into the valve body for the firstconical indentation, where the first insert is made of stainless steel.Likewise, a second insert 82 (see FIG. 4 ) can be press fit into thevalve body for the second conical indentation, where the second insertis made of stainless steel. Yet further, a third insert 84 (see FIG. 7 )can be press fit into the valve body for the third conical indentation,where the third insert is made of stainless steel.

In the illustrated embodiment, the pressure-vacuum valve can open at afirst predetermined positive pressure within the storage tank in orderto allow the excessive positive pressure to vent to atmosphere, e.g.,via the first valve. Also, an excessive and rapid positive pressure inthe storage tank, e.g., from being filled, can open at a secondpredetermined pressure within the storage tank in order to allow theexcessive positive pressure to vent to atmosphere, e.g., via the secondvalve. The pressure-vacuum valve can also open at a predetermined thirdpressure level (e.g., a predetermined vacuum level) within the storagetank to allow the storage tank to vent to atmosphere, e.g., via thethird valve. In this regard, the second predetermined pressure is higherthan the first predetermined pressure so that the second pressure reliefvalve performs emergency venting in the case of a rapid increase instorage tank pressure. However, in practice, the cracking pressures forthe first and second pressure relief valves and the vacuum relief valvecan be set in accordance with national and local fire codes.

In-Line Pressure-vacuum Valve Test Unit

Aspects herein further provide an inline pressure-vacuum valve test unitthat allows testing in place of a corresponding pressure-vacuum valve,e.g., the pressure vacuum valve 26 described above with reference toFIG. 1 -FIG. 8 . In this regard, the inline pressure-vacuum valve testunit can form part of a inline pressure-vacuum valve test system, e.g.,in combination with a vent pipe and/or pressure-vacuum valve.

It is sometimes desirable, and in certain circumstances, required, thatpressure-vacuum valves are inspected to ensure proper operationaccording to predefined standards. Conventionally, this requiresdisassembling the pressure-vacuum valve from a corresponding vent pipe,attaching the pressure-vacuum valve to a test fixture, and testing thepressure-vacuum valve according to predefined standards. Depending uponthe outcome, the pressure-vacuum valve may be returned to service,repaired, or replaced. Regardless, a pressure-vacuum valve must bere-installed back into the vent pipe. This takes considerable time, andplaces wear on the vent pipe. This also creates an opportunity forerrors in operation regardless of testing outcome because thepressure-vacuum valve is normally tested in a test fixture removed fromthe vent pipe and is thus, out of context of its intended application.Thus, a positive test result in the test apparatus may not translate toa similar outcome when installed in the vent pipe, e.g., due todirt/debris, airflow, and other factors. Aspects herein solve this byproviding an inline test fixture that becomes part of the vent pipe, andallows proper testing in place of a corresponding pressure-vacuum valvewithout disturbing the corresponding storage tank.

Referring to FIG. 9 , an in-line pressure-vacuum valve test unit 100includes a body 102, having a tank-side end 104, a valve-side end 106,and an axial passageway 108 extending entirely through the body from thetank-side end 104 to the valve-side end 106.

Referring briefly to FIG. 10 , which illustrates a bottom view of thetest unit 100 of FIG. 9 , the axial passageway 108 defines a tank-sideport 110 on an end face thereof. Correspondingly, referring briefly toFIG. 11 , a top view of the test unit of FIG. 9 illustrates that theaxial passageway 108 defines a valve-side port 112 on an end facethereof. Referring to FIG. 10 and FIG. 11 , in the illustrated example,the end face of the tank-side end 104 is generally circular. In thisregard, the tank-side port 110 can have any desired shape, but isconstrained to fit within a semicircle (exits the body 102 within onlyone half of the end face). Likewise, in the illustrated exampleembodiment the end face of the valve-side end 106 is generally circular.In this regard, the valve-side port 112 can have any desired shape butis constrained to fit within a semicircle (exits the body 102 withinonly one half of the end face), such that the tank-side port 110 and thevalve-side port are opposite of each other. In practice, the body 102,tank-side end 104, valve-side end 106, or combinations thereof can takeon different shapes or configurations.

Referring back to FIG. 9 , the body 102 also includes a test port 114 ina sidewall of the body 102 A radial passageway 116 extends from the testport 114 into the axial passageway 108.

Referring to FIG. 12 , a cross section of the in-line pressure-vacuumvalve test unit 100 is shown taken along line A-A in FIG. 10 and FIG. 11. As best illustrated in FIG. 12 , the axial passageway 108 is definedby a first axial segment 108A, a shoulder segment 108B, and a secondaxial segment 108C. The shoulder segment 108B aligns with the radialpassageway 116 so as to connect the radial passageway 116 with the axialpassageway 108. More particularly, the in-line pressure-vacuum valvetest unit 100 of FIG. 12 illustrates a configuration having first axialsegment extending from the tank-side port into the body, the secondaxial segment extending from the valve-side port into the body where thesecond axial segment is offset from the first axial segment, and ashoulder segment connecting the first axial segment to the second axialsegment.

A cap 118 is user attachable to, and removable from the test port 114.For instance, the cap 118 can be user attachable to the test port 114,thereby sealing access from outside the in-line pressure-vacuum valvetest unit into the axial passageway. In this configuration, a test probeis insertable into the test port 114 when the cap 118 is removed fromthe test port 114. For instance, the cap 118 can threadably couple, snapin, press fit in, press fit over, or otherwise form a seal therebysealing access from outside the in-line pressure-vacuum valve test unit100 into the axial passageway 108.

Referring to FIG. 13 , a test probe 120 is also provided. The test probe120 includes a cylindrical tube body 122 having a hollow 124therethrough. The tube body 122 defines a probe end 126 and a plug end128. The probe end 126 can include attachment features for fittings,etc., e.g., to attach a positive pressure source, vacuum source, etc.The plug end 128 includes at least one sealing member 130. In an exampleembodiment, the test probe 120 comprises at least one sealing member 130implemented as an O-ring that is positioned along an end portion thereof(e.g., proximate to the plug end 128) that extends into the shouldersegment 108B of the axial passageway 108 so as to form a seal therewith.

For instance, as illustrated, two sealing members 130 are implemented asO-rings. Each O-ring may seat in a groove or other structure to hold theO-rings to the plug end 128. In this regard, the plug end 128 isdesigned to have a tight tolerance with regard to the shoulder segment108B (FIG. 12 ).

Referring to FIG. 14 , the cap 118 of FIG. 12 is removed, this exposingthe radial passageway 116 to atmosphere via the test port 114. With thecap 118 removed, the test probe 120 is inserted into the test port 114and secures to the body 102.

When inserted into the test port 114, the test probe 120 extends throughthe radial passageway 116 and into the axial passageway 108. Forinstance, as illustrated, the plug end 128 of the test probe 120 engagesthe shoulder segment 108B of the axial passageway 108 such that theO-rings form a sealing relationship with the sidewalls of the shouldersegment 108B. In this regard, a seal is effectively formed between thetank-side port 110 and the test probe 120 via the O-rings preventingflow from the tank-side through the shoulder segment 108B. However, thetest probe 120 has a hollow therein. As such, a positive pressure ornegative pressure introduced in the hollow of the test probe 120 passesthrough the shoulder portion via the tube body 122 into the axialsegment 108C, thus exiting upstream to the pressure-vacuum valve. Inthis regard, the pressure-vacuum valve can be tested in place by merelyinstalling the test probe 120 into the test port 114.

In some embodiments, the test probe 120 can be permanently installed,wherein, a cap can be utilized to seal the access to the test probe 120.Here, the test probe 120 is installed so that in a default state, thetest probe 120 does not block a pathway between a correspondingpressure-vacuum valve, e.g., the pressure vacuum valve 26 describedabove with reference to FIG. 1 -FIG. 8 , and a pathway to acorresponding storage tank. However, in a test state, the test probe 120blocks the pathway between the pressure-vacuum valve and the storagetank as described more fully herein. For instance, the test probe 120can thread, slip, snap or otherwise traverse between the default stateand test state. In some embodiments, the test probe 120 can threadablyconnect, press fit, snap into or otherwise secure to the body 102.

Thus, the test probe seals the axial passageway between the tank-sideport and a valve-side port. Moreover, the hollow in the test probecooperates with the axial passageway to create a path through the hollowin the test probe, into the axial passageway, and through the valve-sideport. In this regard, a distal end of the test probe receives aconnection from a test apparatus capable of creating at least one of apositive pressure and a vacuum.

Referring to FIG. 15 and FIG. 16 , an example of a vent pipe isillustrated according to aspects herein. The vent pipe system includes afirst vent pipe section 20 and a second vent pipe section 22. Asillustrated, an in-line pressure-vacuum valve test unit 100 is upstreamof the first vent pipe section 20. An in-line pressure-vacuum valve 26is upstream of the in-line pressure-vacuum valve test unit 100. Thesecond vent pipe section 22 is upstream of the in-line pressure-vacuumvalve 26. The in-line pressure-vacuum valve test unit 100 is intendednot to be a replacement item. As such, the in-line pressure-vacuum valvetest unit 100 can be permanently attached to the first vent pipe section20, threadably attached to the first vent pipe section 20, etc.

The in-line pressure-vacuum valve 26, as disclosed herein, has onlythree moving parts, all of which are balls, thus providing a highlyreliable pressure-vacuum valve that represents a significant improvementover previous pressure-vacuum valves. However, in some circumstances, itmay be desirable to remove the in-line pressure-vacuum valve 26 from thevent pipe system. In this regard, a securement, e.g., clamps 140 can beused to temporarily secure the in-line pressure-vacuum valve to the ventpipe system.

Alternatively, as illustrated in FIG. 17 , the in-line pressure-vacuumvalve 26 can threadably connect to, the in-line pressure-vacuum valvetest unit 100 (or first vent pipe section). In other embodiments, thein-line pressure-vacuum valve 26 can bolt, threadably connect, press fitin, compression fit or otherwise secure (permanently or temporarily tothe corresponding vent pipe system.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the invention. Asused herein, the singular forms “a”, “an” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. It will be further understood that the terms “comprises”and/or “comprising,” when used in this specification, specify thepresence of stated features, integers, steps, operations, elements,and/or components, but do not preclude the presence or addition of oneor more other features, integers, steps, operations, elements,components, and/or groups thereof.

The description of the present invention has been presented for purposesof illustration and description, but is not intended to be exhaustive orlimited to the invention in the form disclosed. Many modifications andvariations will be apparent to those of ordinary skill in the artwithout departing from the scope and spirit of the invention.

Having thus described the invention of the present application in detailand by reference to embodiments thereof, it will be apparent thatmodifications and variations are possible without departing from thescope of the invention defined in the appended claims.

What is claimed is:
 1. A flow-through pressure-vacuum valve systemcomprising: a flow-through pressure-vacuum valve; a first vent pipesection that couples the flow-through pressure-vacuum valve to a storagetank; and a second vent pipe section that couples the flow-throughpressure-vacuum valve to atmosphere; wherein the flow-throughpressure-vacuum valve comprises: a first pressure relief passagewaycoupling the first vent pipe to the second vent pipe; a second pressurerelief passageway coupling the first vent pipe to the second vent pipe;a first pressure relief valve closing the first passageway, the firstpressure relief valve comprising: a first valve seat and a first valvemember, the first valve member moved into the first valve seat and heldtherein by gravity to close the first passageway, the first valve memberbeing moved from the first valve seat to open the first passageway whenpressure in the first vent pipe section exceeds pressure at the secondvent pipe section by a first predetermined pressure differential; asecond pressure relief valve closing the second passageway, the secondpressure relief valve comprising: a second valve seat and a second valvemember, the second valve member moved into the second valve seat andheld therein by gravity to close the second passageway, the second valvemember being moved from the second valve seat to open the secondpassageway according to a select one of: when pressure in the first ventpipe section exceeds the pressure at the second vent pipe section by asecond predetermined pressure differential, which is greater than thefirst predetermined pressure differential; or when pressure in the firstvent pipe section is less than the pressure at the second vent pipesection by a second predetermined pressure differential.
 2. Theflow-through pressure-vacuum valve of claim 1, wherein: the first valveseat of the first pressure relief valve comprises a first conicalindentation in the valve body; the first valve member comprises a firstfree-floating spherical ball received in the first conical indentationand held therein by gravity; the second valve seat of the secondpressure relief valve comprises a second conical indentation in thevalve body; and the second valve member comprises a second free-floatingspherical ball received in the second conical indentation and heldtherein by gravity.
 3. The flow-through pressure-vacuum valve of claim2, wherein: a first cracking pressure associated with the first pressurerelief valve is determined by a ball size of the first free-floatingspherical ball, a composition of the first free-floating spherical ball,and a sidewall angle of the first conical indentation; and a secondcracking pressure associated with the second pressure relief valve isdetermined by a ball size of the second free-floating spherical ball, acomposition of the second free-floating spherical ball, and a sidewallangle of the second conical indentation.
 4. The flow-throughpressure-vacuum valve of claim 1, wherein the flow-throughpressure-vacuum valve is connected into the first vent pipe section soas to position the flow-through pressure-vacuum valve at a height ofless than six feet (approximately 1.83 meters) from the surface fromwhich the vent pipe emerges from the fuel storage tank.
 5. Theflow-through pressure-vacuum valve of claim 1, wherein the flow-throughpressure-vacuum valve is connected into the first vent pipe section soas to position the flow-through pressure-vacuum valve at a height of upto four feet (approximately 1.22 meters) from the surface from which thevent pipe emerges from the fuel storage tank.
 6. An in-linepressure-vacuum valve test unit comprising: a body having a tank-sideend, a valve-side end, and an axial passageway extending entirelythrough the body from the tank-side end to the valve-side end, the axialpassageway defining a tank-side port and a valve-side port; a test portin a sidewall of the body; a radial passageway extending from the testport into the axial passageway; and a test probe having a hollowtherethrough, the test probe inserted into the test port such that: thetest probe extends through the radial passageway and into the axialpassageway; the test probe seals the axial passageway between thetank-side port and a valve-side port; and the hollow in the test probecooperates with the axial passageway to create a path through the hollowin the test probe, into the axial passageway, and through the valve-sideport.
 7. The in-line pressure-vacuum valve test unit of claim 6 furthercomprising a cap that is user attachable to, and removable from the testport thereby sealing access from outside the in-line pressure-vacuumvalve test unit into the axial passageway, wherein: the test probe isinsertable into the test port when the cap is removed from the testport.
 8. The in-line pressure-vacuum valve test unit of claim 6, whereinthe axial passageway comprises: a first axial segment extending from thetank-side port into the body; a second axial segment extending from thevalve-side port into the body, the second axial segment offset from thefirst axial segment; and a shoulder segment connecting the first axialsegment to the second axial segment.
 9. The in-line pressure-vacuumvalve test unit of claim 8, wherein: the test probe comprises at leastone O-ring along an end portion thereof that extends into the shouldersegment of the axial passageway of the in-line pressure-vacuum valvetest unit so as to form a seal therewith.
 10. The in-linepressure-vacuum valve test unit of claim 6, wherein a distal end of thetest probe receives a connection from a test apparatus capable ofcreating at least one of a positive pressure and a vacuum.
 11. Anin-line pressure-vacuum valve test system comprising: an in-linepressure-vacuum valve test unit comprising: a body having a tank-sideend, a valve-side end, and an axial passageway extending entirelythrough the body from the tank-side end to the valve-side end, the axialpassageway defining a tank-side port and a valve-side port; a test portin a sidewall of the body; a radial passageway extending from the testport into the axial passageway; and a test probe having a hollowtherethrough, the test probe inserted into the test port such that; thetest probe extends through the radial passageway and into the axialpassageway; the test probe seals the axial passageway between thetank-side port and a valve-side port; and the hollow in the test probecooperates with the axial passageway to create a path through the hollowin the test probe, into the axial passageway, and through the valve-sideport; a vent pipe having a first vent pipe segment coupled to thetank-side port; and a pressure-vacuum valve coupled to the in-linepressure-vacuum valve test unit.
 12. The in-line pressure-vacuum valvetest system of claim 11, wherein the pressure-vacuum valve is in-linewith the vent pipe upstream of the in-line pressure-vacuum valve testunit.
 13. The in-line pressure-vacuum valve test system of claim 12,wherein the flow-through pressure-vacuum valve is positioned at a heightof less than six feet (approximately 1.83 meters) from the surface fromwhich the vent pipe emerges from the fuel storage tank, and the in-linepressure-vacuum valve test unit is in-line with the vent pipe below theflow-through pressure-vacuum valve.
 14. The in-line pressure-vacuumvalve test system of claim 12, wherein the flow-through pressure-vacuumvalve is positioned at a height of up to four feet (approximately 1.22meters) from the surface from which the vent pipe emerges from the fuelstorage tank, and the in-line pressure-vacuum valve test unit is in-linewith the vent pipe below the flow-through pressure-vacuum valve.
 15. Thein-line pressure-vacuum valve test system of claim 11, wherein thepressure-vacuum valve comprises: a valve body having a tank-side openingand a vent-side opening; a pressure relief passageway that extendsthrough the valve body from the tank-side opening to the vent-sideopening; a vacuum release passageway that extends through the valve bodyfrom the tank-side opening to the vent-side opening; a pressure reliefvalve within the pressure relief passageway, the pressure relief valvecomprising: a valve seat and a valve member, the valve member moved intothe valve seat and held therein by gravity to close the pressure reliefpassageway, the valve member being moved from the valve seat to open thepressure relief passageway when pressure at the tank-side opening of thevalve body exceeds pressure at the vent-side opening of the valve bodyby a first predetermined pressure differential; a vacuum relief valvewithin the vacuum release passageway, the vacuum relief valvecomprising: a valve seat and a valve member, the valve member moved intothe valve seat and held therein by gravity to close the vacuum reliefpassageway, the valve member being moved from the valve seat to open thevacuum relief passageway when pressure at the tank-side opening of thevalve body is less than the pressure at the vent-side opening of thevalve body by a predetermined pressure differential.